1. Field of the Invention
The present invention relates generally to a collated fastener strip and, in particular, to an improved collated strip of headless or slight headed nails which can be used in magazines of pneumatic fastener driving tools which are designed to accept headed nails.
2. Description of the Prior Art
The use of pneumatic fastener driving tools have become very popular in all instances where it is necessary to fasten pieces of wood together. Workers in industries such as house construction and furniture manufacturing regularly use these tools to increase productivity as well as improve quality and appearance. An example of one such tool is taught in U.S. Pat. No. 5,368,213, which is assigned to the assignee of the present invention and is hereby incorporated by reference. This tool is of the type generally characterized as having a guide body extending laterally from the pneumatic member at a forward end and including a driver extending from the pneumatic member through a drive channel in the guide body. A magazine is affixed to the underside of the pneumatic member with an open feed end extending into the guide body and having a tensioning mechanism for feeding fasteners into the drive channel.
The magazine taught in the '213 patent contains a series of complimentary parallel grooves on either side of the pathway which carries the fasteners as they are fed into the drive channel. These grooves accommodate the heads of the fasteners as they are transported toward the drive channel of the tool under the force of the tensioning mechanism, providing stability and support for the feeding of the fasteners and adding to the overall reliability of the operation of this tool.
Headless or slight headed nails, often called "finish" nails in the trade, are used for attaching trim boards, assembling furniture, and in other applications where headed fasteners would be unsightly or may contribute to marring the finish of the workpiece when they are applied. The holding power of headless nails, however, is considerably less than that provided by headed nails; therefore, they are normally used in performing finish work, where holding forces needed are not as critical.
One shortcoming of a tool of the type described in the '213 patent is that it cannot reliably drive headless fasteners, as this type of fastener has a tendency to jam the tool, as the absence of the head on the fastener for guidance in the magazine grooves allows undesired movement of the fastener strip as it is advanced within the magazine.
This problem has been addressed several times in the prior art. U.S. Pat. No. 3,720,364, which issued in 1973 to Maestri, describes a fastener driving tool which has a magazine designed for driving headless nails of different lengths. This is accomplished by the use of movable members which are selectively advanced into position and locked to create an acceptable passageway for different sizes of headless nails.
U.S. Pat. No. 4,174,802, which issued in 1979 to Maestri, describes a magazine for a fastener driving tool which can accommodate nails of different lengths and head sizes. The side wall of the magazine is adjustable such that it can be positioned to guide the nails by the point and sides of the nail strip.
Although these prior art references teach several magazines which are capable of driving both headed and headless nails, each has particular deficiencies in the complexity in the design of its magazine and the operation to accommodate different sizes of nails.